Remote control device especially for conveying, spraying and distributing machines for concrete and mortar

ABSTRACT

The invention relates to a remote control device for mobile and stationary concrete pumps. The remote control device has a central control device to control groups and signalling units of the concrete pump and a remote control appliance connected to the central control device via a multicore remote control cable. The central control device has an emergency stop switch gear remote controlled by a mechanically actuatable emergency stop switch fitted in the remote control appliance, the power supply to which is taken via a forced first switch contact of the emergency stop switch and which triggers an emergency stop if the power supply fails. In order to ensure reliable emergency cut-off even in the event of a short circuit in the emergency stop system when the emergency stop switch is actuated, there is an overload fuse in the central control-side lead to the first switch contact designed as a break contact. In addition, there is in the emergency stop switch a second forced switch contact designed as a make contact, the first connection of which is connected to the ground terminal of the power source and the second connection of which is connected to the second connection of the first switch contact within the remote control appliance.

FIELD OF THE INVENTION

The invention relates to a remote control device, especially forconveying, spraying and distributing machines for concrete and mortar,having a central control device for controlling aggregates andsignalling elements, and having a remote control unit connected to thecentral control device through a multicore remote control cable. Thecentral control device has an emergency stop switch device for main andcontrol circuits leading to the aggregates and signalling elements,which can be remote controlled by means of a manually mechanicallyactuatable emergency stop switch or key arranged in the remote controlunit. The power supply is guided through a forced first switch contactof the emergency stop switch, which contact is designed as a breakcontact, and which triggers an emergency cut-off when the power supplyis interrupted.

BACKGROUND OF THE INVENTION

In remote control devices for machines of the above type, thepossibility of an emergency cut-off in dangerous situations, which canoccur due to malfunctions or incorrect operations, on the one hand, ordue to happenings in surrounding areas on the other hand, isintolerable. All instantaneous sequences of movement are usuallyinterrupted during an emergency cut-off. Since the emergency stopfunction is thus of a central importance for reasons of operationalsafety, suitable precautions must be taken, which guarantee also duringa breakdown, a reliable emergency cut-off. In cable remote controldevices, consideration must particularly be noted that the longmulticore remote control cables can experience a short in a cable in theemergency stop circuit during a rough building site operation, throughwhich the switch contact of the emergency stop switch is bridged, andthus no longer functions. The operator notices hereby only in a case ofdanger during an operation of the emergency stop switch that the remotecontrol cable is no longer in order.

Starting out from this, the basic purpose of the invention is to furtherimprove the remote control device of the above-disclosed type in such amanner that also in the case of a short in a cable in the emergency stopcircuit, especially in the area of the remote control cable, anemergency cut-off is still triggered by operating the emergency stopswitch.

To attain this purpose, the characteristic combinations disclosed inclaims 1 and 3 are suggested. An advantageous development of theinvention results from the dependent claim.

The solution of the invention is based on the thought that also in thecase of a short in a cable in the emergency stop circuit it must beassured that during operation of the emergency stop switch, the powersupply to the emergency stop switch device is interrupted.

SUMMARY OF THE INVENTION

In order to achieve this, it is suggested according to a firstmodification of the invention that the first switch contact is connectedat its first connection through a first cable core of the remote controlcable and an overload fuse to the "hot" pole of a central control sidevoltage source, and with its second connection through a second cablecore of the remote control cable to a power supply connecting terminalof the emergency stop switch device. The emergency stop switch has inaddition a forced second switch contact designed as a make contact, thefirst connection of which is connected to the ground pole of the voltagesource, and the second connection of which is short-circuited within theremote control unit to the second connection of the first switchcontact, and that the first and the second switch contact react timelyone after the other upon operation of the emergency stop switch forminga switch gap. The first and the second switch contact of the emergencystop switch can also be combined in a change-over switch.

With this measure it is achieved that upon operation of the emergencystop switch in the usual case, the power supply connection of theemergency stop switch device is switched over to ground potential andthus triggers the emergency cut-off. The operation of the emergency stopswitch leads to a short circuit between the "hot" pole and the groundpole of the voltage source and thus to the triggering of the overloadfuse upon a short in a cable in the emergency stop circuit. The "hot"pole of the voltage source is separated by this and the power connectingterminal is changed to ground potential triggering the emergencycut-off.

In a second modified solution of the invention, in which the switchcontact of the emergency stop switch is also connected at its firstconnection through a first cable core of the remote control cable to a"hot" pole of a center control side voltage source and with its secondconnection through a second cable core to a power supply connectingterminal of the emergency stop switch device, the first and/or secondcable core has a shielding cover connected to the ground pole of thevoltage source. With this measure it is also achieved, upon a short in acable in the emergency stop circuit in the area of the remote controlcable, that a short circuit triggers the overload fuse. With this it isassured that the emergency stop switch device becomes powerless andtriggers the emergency cut-off.

The short in a line is in both cases indicated to the operator by thereaction of the overload fuse. In order to achieve this safety feature,it was necessary, up to now, to design the emergency stop circuitredundant, thus having at least with two channels, with the consequencethat a larger cable and a larger plug were necessary, or the functioningoperation of the remote control had to be limited.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be discussed in greater detail hereinafter inconnection with one exemplary embodiment schematically illustrated inthe drawing.

The single FIGURE shows a section of an electric circuit diagram of acable remote control device with a remote-controlled emergency stopswitch unit, for example used with an automated concrete pump.

DETAILED DESCRIPTION

The electrical circuit diagram includes a section from a central controldevice 10 with an emergency stop switch device 12 and a section from aremote control unit 14 for an automated concrete pump. The concrete pumphas aggregates or parts 15 and signalling elements 17. The remotecontrol unit 14 is connected to the central control 10 through amulticore remote control cable 16 and suitable plug connections 18, 20.Of the, for example, thirty-two cable cores 22, the drawing shows atotal of five.

The central control 10 and the remote control unit 14 are supplied withpower from a power supply with, for example, 24 V direct current oralternating current, to the "hot" positive pole 24 (phase) and thegrounded pole 26.

The emergency stop switch device 12 has a plurality of connectingterminals 28, 30, 32, 34 and 36 and 40, which can be externallyswitched. The emergency stop switch device 12 is supplied with powerthrough the terminals 28 and 30, whereby the terminal 30 can beconnected galvanically to the ground pole 26 and the terminal 28 throughan emergency stop circuit to the hot pole 24. The terminals 36 areintended for the external switching of internal circuits of theemergency stop switch 12, whereas the terminals 40 and 32 and 34 areintended for controlling the external main and control circuits 29, 31allowing for the operation of the emergency stop functions. Theemergency stop switch device 12 is activated with the start key 42. Thecontacts 40 are thereby closed and the contact 32, 34 is opened. Byoperating one of the emergency stop switches 44, 46 in the area of thecentral control or in the area of the remote control unit 14, thecontacts 40 or 32, 34 fall back into their base position and trigger anemergency stop. This is done by the connection between the pole 24 ofthe power supply and the power supply terminal 28 of the emergency stopswitch device being interrupted by the emergency stop switches 44 and46. The respective current supply line can be selectively switched tothe remote control unit 14 (as illustrated) or to a local control. Anoverload fuse 54 is provided on the input side in the lead 50, which isconnected to the line 52 of the remote control unit 14 through the cablecore 22'. The line 52 is connected in the remote control unit 14 throughthe switch contact 56 of the emergency stop key 46, which switch contactis designed as a break contact, and thus to the return circuit 58, thecable core 22", and the central control side return circuit 60 to thepower supply terminal 28 of the emergency stop device 12 respectively.The terminal 58 is furthermore connected to a terminal 62 of a switchcontact 64 of the emergency stop switch 46, which switch contact 64 isdesigned as a make contact, the other terminal 66 of which is connectedthrough the cable core 22'" to a grounded wire 67 leading to the groundpole 26 of the central control.

If the emergency stop switch 46 is thus operated, the contact 56 opensfirst and interrupts in this manner the power supplied to the powersupply terminal 28 of the emergency stop switch device 12 triggering anemergency cut-off. Shortly after the contact 46 opens, the contact 64closes and places the input of power supply terminal 28 to groundpotential. The emergency stop switch 12 continues to remain currentlessin its emergency cut-off state.

It happens again and again in a rough building-site operation that ashort in a cable occurs in the individual cores 22 of the remote controlcable 16. The first and/or second cable core 22', 22" has a shieldingcover 22A connected to ground. A short in a cable between the cores 22'and 22" leads thereby to a bridging of the switch contact 56. Thus, insuch a breakdown case an opening of the switch contact 56 upon operationof the emergency stop switch 46 will alone not yet lead to the releaseof an emergency cut-off. Only when the contact 64 is closed, a shortcircuit occurs between the lead 50 and the ground wire 66 in the area ofthe short in the cable, through which the fuse 54 is triggered and thepower supply through the line 50 to the power supply terminal 28 isinterrupted. This guarantees that also in the case of such a breakdownan emergency cut-off occurs through the device 12.

As has been discussed above, the contacts 32, 34 of the emergency stopswitch 12 are open during the activating phase so that the contact 70 ofthe relay 68 arranged in the respective circuit drops off into its openposition. The contact 32 falls in the emergency stop state back into itsbase position illustrated in the drawing so that the relay contact 70reaches its closing position and loads the alarm lamps 72 and 74 withcurrent through the fuse 76 and illuminates them.

In conclusion, the following is to be stated: The invention relates to aremote control device, in particular for movable and stationary concretepumps. The remote control device has a central control device 10 forcontrolling aggregates 15 and signal units 17 of the concrete pump and aremote control unit 14 connected to the central control device 10through a multicore remote control cable 16. The central control devicehas an emergency stop switch device 12, which can be remote controlledby means of a mechanically operable emergency stop switch 46 arranged inthe remote control unit 14, the power supply of which emergency stopswitch device 12 is taken via a forced first switch contact 56 of theemergency stop switch 46 and which triggers an emergency cut-off if thepower supply is interrupted. In order to guarantee reliable emergencycut-off even in the event of a short circuit in the emergency stopsystem when the emergency stop switch 46 is actuated, there is anoverload fuse 54 in the central control-side lead 50 to the first switchcontact 56 designed as a break contact. Furthermore, there is in theemergency stop switch 46 a second forced switch contact 64 designed as amake contact, the first terminal 66 of which is connected to the groundterminal 26 of the voltage source, and the second terminal 62 of whichis connected to the second terminal 58 of the first switch contact 56within the remote control unit 14. The embodiments of the invention inwhich an exclusive property or privilege is claimed are defined asfollows:

In the claims:
 1. A switch device comprising:a remote control unithaving a mechanically actuable emergency stop switch, said emergencystop switch including first and second switch contacts, each switchcontact having first and second terminals, said emergency stop switchbeing adapted to cut-off operation of a machine even if power suppliedthereto is interrupted; a central control device for controlling partsand signalling elements of a machine, the central control device havingan emergency stop switch device operatable by one of said emergency stopswitch a key, the emergency stop switch device including a power supplyconnecting terminal; a power supply having a positive pole and a groundpole, the positive pole being connected through a fuse to the firstterminal of the first switch contact of the emergency stop switch; and amulticore remote control cable connecting the central control device tothe remote control unit; the second terminal of the first switch contactbeing connected to the power supply connecting terminal of the emergencystop switch device, the first terminal of the second switch contactbeing connected to the ground pole of the power supply, the secondterminal of the second switch contact being connected to the secondterminal of the first switch contact; the first switch contact of theemergency stop switch being adapted to break contact in an emergencystop and being connected at the first terminal through a first cablecore of the remote control cable to the positive pole of the powersupply, the second terminal of the first switch contact being connectedthrough a second cable core of the remote control cable to the powersupply connecting terminal of the emergency stop switch device, thesecond switch contact being adapted to make contact in an emergencystop, the first terminal of the second switch contact being connectedthrough a third cable core of the remote control cable to the groundpole of the power supply, the first and the second switch contact beingadapted to be forcedly guided and being adapted to react timely oneafter the other upon operation of the emergency stop switch.
 2. Theswitch device according to claim 1, wherein the first and second switchcontacts are combined in a changeover switch.
 3. The switch deviceaccording to claim 1, wherein said power supply is a voltage source,said voltage source being housed in said central control device.
 4. Theswitch device according to claim 3, wherein said first and second cablecores have a shielding cover connected to said ground pole.
 5. A switchdevice comprising:a central control device for controlling parts andsignalling elements of a machine, the central control device having anemergency stop switch device for signaling main and control circuitsconnected to stop operation of the parts and the signalling elements,the emergency stop switch device having a power supply terminal, amechanically actuable emergency stop switch being adapted to signal anemergency stop to the emergency stop switch device, the emergency stopswitch having a switch contact, a power supply supplying power to thecentral control and emergency stop switch, the power supply havingpositive and ground poles, the emergency stop switch being adapted totrigger an emergency cut-off upon interruption of the power supply, thepower supply being housed in the central control device, the switchcontact having first and second terminals, the first terminal beingconnected through an overload fuse to the positive pole, the secondterminal being connected to the power supply connecting terminal of theemergency stop switch device, a remote control unit having a multicoreremote control cable connected to the central control device, theemergency stop switch being arranged in the remote control unit, thefirst terminal of the switch contact of the emergency stop switch beingconnected through a first cable core of the remote control cable to thepositive pole of the power supply and the second terminal beingconnected through a second cable core of the remote control cable to thepower supply terminal of the emergency stop switch device, and ashielding cover connected to the ground pole of the voltage sourcecovering at least one of the first and second cable cores.
 6. A devicefor controlling operation of a material distributing machine, comprisinga central control device, a remote control unit, a multicore cableconnecting said central control device and said remote control unit, andan electrical power supply having a positive pole and a ground pole,saidcentral control device including circuits controlling parts of themachine and emergency stop device having means for manually stoppingoperation of the machine and having an output and a power supplyterminal, said output of said emergency stop device being connected tosaid circuits, said remote control unit including an emergency stopswitch for stopping operation of the machine when power from the powersupply is interrupted to said remote control device, said emergency stopswitch having operation and stop positions and first and second switchcontacts, said first switch having first and second terminals, saidfirst and second terminals being electrically connected in the operationposition of said emergency stop switch and being open circuited in thestop position of said emergency stop switch, said second switch contacthaving third and fourth terminals, said third and fourth terminals beingopen circuited in the operation position of said emergency stop switchand being electrically connected in the stop position of said emergencystop switch, said first terminal being connected to said positive poleof said electrical power supply through a first cable of said multicorecable, said second terminal being connected to said power supplyterminal of said emergency stop device through a second cable of saidmulticore cable, said third terminal being connected to said ground polethrough a third cable of said multicore cable, said fourth terminalbeing connected to said second terminal, and said second switch contactconnecting the positive pole to the ground pole preventing electricalpower from reaching said power supply terminal even if said multicorecable is shorted to stop operation of the machine when the emergencystop switch is in the stop position.
 7. The device according to claim 6,wherein said central control device includes an overload fuse and acentral stop switch, said fuse being connected between said positivepole and a fifth terminal of said central stop switch, and a sixthterminal of said central stop switch being connected to said firstterminal of said first switch contact through said first cable.